Various types of nebulizers have been used in commerce for a variety of applications and are well known in the art. One common application for a nebulizer is in the medical industry. Such a nebulizer has been used in the medical industry for effective delivery of medicines to a patient's lungs. An example of a nebulizer capable of delivering medicine to a patient's lungs is disclosed in U.S. Pat. No. 4,746,067 to Steven A. Svoboda which is incorporated herein by reference and is generally introduced as prior art in FIG. 1.
This prior art nebulizer is a device for aerosolizing a liquid medicine 7 with a pressurized gas (the source of which is not shown) which is typically compressed air. The prior art nebulizer includes a container 1 for holding liquid medicine 7, a mixing mechanism 50 and a deflector member 11. Mixing mechanism 50 comprises a venturi tube 2 and a liquid conduit means 6. Venturi tube 2 has an upstream opening 3 adapted for connection to the source of pressurized gas, a throat portion 4 and a discharge opening 5. Liquid conduit means 6 is connected to container 1 and has an outlet opening 8 adjacent to a downstream end 9 of throat portion 4. Venturi tube 2 is dimensioned and positioned to withdraw liquid medicine 7 from reservoir 19 and through liquid conduit means 6 and to project a mixture of liquid and gas out of discharge opening 5 at a high velocity in a nebulized liquid/gas stream.
A deflector member 11 is positioned adjacent to and disposed from discharge opening 5 of venturi tube 2 and has a surface 12 intersecting the liquid/gas stream and causing a dispersion of the liquid/gas stream in a second direction different from the first direction. Deflector member 11 is employed to further reduce the liquid droplet size in the nebulized liquid/gas stream thereby causing a fine mist which dispersed about an interior chamber of container 1.
With the prior art being replete with nebulizers, some other nebulizers are described in U.S. Pat. No. 5,287,847 to Piper et al., U.S. Pat. No. 5,209,225 to Glenn, U.S. Pat. No. 4,657,007 to Calin et al., U.S. Pat. No. 4,588,129 to Shanks, U.S. Pat. No. 4,512,341 to Lester, U.S. Pat. No. 3,762,409 to Lester, U.S. Pat. No. 3,744,722 to Burns and U.S. Pat. No. 3,097,645. In one form or another, all of these patents as well as other prior art nebulizers teach a nebulizer device which mixes a pressurized aerosolizing gas with a liquid to produce a stream of nebulized liquid and gas predicated upon the commonly known venturi principle. Often, this stream is directed to a deflector member which further reduces the size of the liquid droplets in the nebulized liquid stream to form a fine mist. The mist disperses throughout the interior chamber of the nebulizer. Particularly in light of the patents noted above, the fine mist of nebulized liquid is inhaled by the user through a tube opened to the ambient air environment. Prior art nebulizers continuously produce the fine mist. Thus, during exhalation, some of the fine mist which typically contains costly medicament exits the container through the tube and into the ambient air environment. This results in wasted medicament.
There is a need in the industry for a breathing circuit apparatus which can be used in combination with a nebulizer device operative to generate an aerosol so that the user can inhale aerosol through his/her nose and/or mouth from the breathing circuit apparatus and thereafter can exhale exhalation gas through the breathing circuit apparatus and into ambient environment. It would be advantageous if the breathing circuit apparatus used in combination with a nebulizer device can create a preselected amount of positive back-pressure on the lungs when the user exhales through the breathing circuit apparatus. In this latter regard, it would also be advantageous if the breathing circuit apparatus included an adjustable outlet valve so that the amount of positive back-pressure on the lungs can be regulated, or be provided with a flapper valve with preselected stiffness for providing back-pressure of from about 5 cm to about 20 cm of water. There is also a need in the industry for breathing circuit apparatus used with a nebulizer device that minimizes loss of aerosolized medicament into the ambient environment to minimize waste of the medication contained in the aerosol and limit contamination of the atmosphere with medicament. It would be advantageous if the aerosolized medicament can be contained in the breathing circuit apparatus as much as possible, particularly during exhalation, so that a health care provider can better provide medicament dosage requirements for the user/patient. It would be further advantageous if the breathing circuit apparatus adapted for use with the nebulizer device has a mouthpiece structure.
With a breathing circuit apparatus adapted for both inhalation and exhalation by the patient, it would be desirable if the breathing circuit apparatus include a drool trap which prevents the user's saliva from contaminating the medicament-containing liquid which is used to generate the aerosolized medicament. It would also be advantageous if the breathing circuit apparatus has an inlet which could be utilized for replenishing the liquid in the nebulizer device without interruption of use or monitoring breathing pressure in the breathing circuit apparatus while in use. The inlet could further be utilized as a sensing port for monitoring breathing cycles and pressures generated by the user/patient to control the timing of the flow of aerosolizing gas to the nebulizer device to occur during only pre-selected intervals during the user/patient's breathing cycles. The present invention satisfies these needs and provides these advantages.